As a kind of a memory device using a magnetoresistance effect element, a magnetic random access memory (MRAM) device having a magnetic tunnel junction (MTJ) structure has attracted attention.
The MRAM device includes a multilayer film made of a hardly etchable material containing a metal, such as, for example, a ferromagnetic substance. In the manufacturing of such an MRAM device, the multilayer film is etched using a mask made of a metallic material, such as, for example, Ta (tantalum), and TiN. In such an etching, a halogen gas has conventionally been used as disclosed in Japanese Patent Laid-Open Publication No. 2012-204408.